1. Field of the Invention
This invention is in the field of preparing higher order cuprate complexes from alkyl, vinyl, benzyl, phenyl or allyl stannane compounds which complexes are useful as reactive intermediate in organic synthesis. In particular the process and compounds of this invention are useful for the addition of the omega chain to cyclopentenones in the synthesis of prostaglandins.
2. Prior Art
The state of the art of higher order cuprate complexes is summarized in Synthesis, #4, p. 325, (1987) where higher order cuprate complexes of the formulae R.sub.t RCu(CN)Li.sub.2, R.sub.t Cu(2-thienyl)CNLi.sub.2, and R.sub.t RCu(SCN)Li.sub.2 and their use are disclosed. R.sub.t represents the group transferred to an organic compound to form a carbon to carbon bond in a subsequent reaction with the complex.
U.S. Pat. No. 4,499,296 describes the preparation of a large number of prostaglandins prepared by the sequence of reactions set out in the following steps:
(i) a stannane compound of the formula ##STR1## is reacted with alkyl lithium in one reaction vessel;
(ii) an organo copper compound is formed in a separate vessel;
(iii) the reagents formed in (i) and (ii) are mixed together and added to a cyclopentenone: ##STR2## to provide prostaglandins of formula I ##STR3## wherein,
R'" is --CO.sub.2 R"";
R"" is hydrogen or lower alkyl containing 1 to 6 carbon atoms;
R' is lower alkyl containing 1 to 6 carbon atoms, vinyl or ethynyl;
R" is alkyl or cycloalkyl containing 3 to 5 carbon atoms; and
the wave line represents R,S stereochemistry.
JACS 94 7210 (1972) describes lithium copper vinyl complexes. Prostaglandin Synthesis, Academic Press, 1977, Chapt. 7 describes prostaglandin synthesis generally. U.S. Pat. Nos. 4,449,296; 4,322,543; 4,578,505; and 4,271,314 describe organotin intermediate in the preparation of prostaglandins.